Simulation of temperature distribution in gas turbine stator blade subjected to different internal coolant gases

Abstract

The gas turbine blade stator is subjected to a severely high temperature of hot incoming gases from the combustor. In order to avoid the melting of the stator, film and internal cooling techniques are applied by using a bypass stream of air from the compressor as a coolant fluid. These techniques have their own merits, but it is limited by some constraints like the value of specific heat of air. In this paper, different gases with higher specific heat are used as a coolant in order to increase the thermal capacity of coolant fluid which in turn increases the amount of transferred heat. The selected gases Helium, Steam, and Ammonia are applied in COMSOL Multiphysics® in order to simulate the cooling process and the temperature distribution. At first, the air is applied and the results show a good agreement with previous literature then the other coolants compare their results with the air. The results show that the Helium affects the cooling process strongly and it cools the blade to safer limits rather than air by about 50%, but it increases von Mises stress by about 71% in comparison with air. The two other coolants also have a good and effective cooling performance, but they almost show an identical performance.